Method of tunneling.



' i/ wmlwm No. 867,392. PATENTBD OCT. 1, 1907.

7 D. MAXWELL.

METHOD OF TUNNELING. APPLICATION 311.21) mm. 4. 1907.

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DAVID MAXWELL, OF DETROIT, MICHIGAN.

METHOD OF TUNNE LING.

Specification of Letters Patent.

Patented Oct. 1, 1907.

Original application filed August 25, 1904, Serial No. 222,040. Renewed February 4, 1907, Serial No. 355,724. Divided and this application filed March 4, 1907. Serial No. 360,350.

To all whom it may concern:

Be it known that 1, DAVID MAXWELL, of Detroit, Wayne county, Michigan, have invented a new and useful Method of Tunneling, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which Figure 1 is a cross-sectional view through a tunnel illustrating the location of drill holes; Fig. 2 is a similar view after the blasting operation; Fig. 3 is a longitudinal vertical section showing the tunnel; and Fig. 4 is a longitudinalhorizontal section of the same.

"his application which is a division of my application, Serial No. 222,040, filed August 25, 1904, has relation to a novel method of tunneling, and it consists in the novel steps and method of operation, all substantially as hereinafter described and pointed out in the claims.

The initial operation in the method of tunneling which I employ is illustrated in Fig. 1, and consists in making a channel cut 2 of arch form and of suitable depth, preferably about four feet, the depth, however, being governed by the length of the channel tool which it is convenient to employ. I also drill in the face of the rock, preferably at the same time with the forming of the channel cut, a series of blast holes 3 which incline upwardly, their precise direction being deter mined by the nature of the rock, as will be understood by those skilled in the art. I also drill at the same time in the face of the rock a series of blast holes 4 above the channel-cut for the purpose of blasting out an exterior space for the accommodation of the timbering and masonry where the rock is soft, and the tunnel therefore requires to be lined.

After the channel 2 has been cut and the holes 3 and 4 drilled as above stated, the drilling and channeling machine is withdrawn from the face of the rock, and the work of blasting is begun. The first blast is made with the top row of the holes 3, and with the holes at the center of the series 4. These blast-holes 3 are directly under the top of the channel-cut and the holes 4 in which the first blasting is done are directly above the same, so that the effect of the first blast is to make a clearance space beneath the apex of the channel-cut 2 and directly above the same and to discharge the loosened rock in great part forwardly, causing it to fall upon aprons at the base of the tunnel as indicated at 3". Some of the loosened rock will, however, remain at the top of the face in which are the holes 3. The next blasting is done in the row of holes 3 next below, and also in the holes 4 at the side of the space above the channel-cut which has been formed by the preceding blast. This discharges an additional mass' of rock from below the channel-cut upon the apron at the base of the tunnel together with the loose rock remaining from the preceding blast, an d also widens the blasted space above the channel. The work of blasting is thus continued, each successive blast being made in a row of holes 3 below the last preceding one, and in holes 4 successively outward from. the middle The distance between the last two rows of holes 4 is preferably small so that only a relatively small amount of work will have to be done in blasting these holes, and a light charge of explosive being used the rock will not be shattered and a solid seat 4 will be formed forthe timbering and masonry to spring from. When the blasting is finally completed it affords a blasted space of the shape indicated in diagram in Fig. 2, the upper portion being of greater width than the lower portion and having seats 4 for the masonry and timbering as above stated.

If desired, the seats 4 can be formed by channeling. At each successive blast the material dislodged thereby falls upon a carrier which extends from side to side of the tunnel, and when the entire face of the rock has thus been blasted, it is transferred from the carrier to cars in the tunnel, and the carrier being withdrawn, the drilling and channeling machine is again advanced, and the work of channeling and drilling followed by blasting is repeated.

As the tunneling proceeds the timbering is set in the widened space at the top of the tunnel and can be continued so as to follow the operation of tunneling very closely, say within about twelve feet of the end of the face of the rock.

The wider space at the top of the tunnel which is formed by the blast-holes 4 is of great advantage because it enables the timbering to be carried on concurrently with the drilling, and enables the drilling and channeling machine to be advanced and drawn back without interference by the timbering, which being in a space around the outline of the tunnel proper leaves a full opening for the passage of the machine. The masom-y is applied preferably when the tunnel is finished. The rails upon which the drilling machine and the loading cars travel are added in sections preferably four feet at a time, after each complete operation of blasting the face of the rock.

Any suitable apparatus may be employed for the purpose of carrying out my invention, but I prefer to employ apparatus of the character described and claimed in my application, Serial No. 222,040, above referred to, and in my application, Serial N 0. 288,879, filed November 24th, 1905..

I What 1 claim is1- l. The herein described method of tunneling, which con sists in preliminarily cutting 01' drilling to outline the cross-section of the tunnel, and also drilling extcriorly of such cross-section atv the top of the tunnel, and subse quently dislodgin; and removing the material contained in the outlined area and in the exteriorly drilled area; substantially as described 2. The herein de. ihed method of tunnelin." which consists in first cuttin or drilling around a cum-section of the material to be removed and removing the material so outlined. and concurrently with the advance of the tunnel excavatingand removing additional material at the upper portion of the tunnel but: exteriorly of the tunnel proper; substantially as described.

:l. The herein described method of tunnelingwhich con si. s in outlining the tunnel proper by a channel cut. and also drilling an enlarged space at the top of the tunnel outside the channel cut, and then blasting out the material within the channel cut and at the outside; substantially as described.

l The herein described method of tunneling; which consi in outlining the tuunel proper by a channel cut, and also drilling outside of the channel cut above and around the upper portion ot' the same. and then removing the material within the channel cut and that: which has been drilled outside of said cut, the removal within the cut being etlected from the top downwardly and the removal outside of the cut being et'iected from the center outwardly substantially as described 5. The herein described method of tunneling which consists in outlining the tunnel proper by a channel cut. and also drilling outside of, above and around the upper portion of such cut. then blasting and removing the material within said out and from the outside drilled area, the blasting and removal of the latter being conducted from the center outwardly; substantially as described 3. The herein described method of tunneliu' which cons in outlining the tunnel by a channel cut, forming a set es of blast-holes extending from the top to the bottom of the face of the rock, blasting out by 51 ssive blasts the entire face of the rock and removing the dislodged material; substantially as described.

in testimony whereof, I have hereunto set my hand.

l).\\'ll) MAXWELL 

